780p or 1080i which one is more expensive and better tech?

yes but the two tvs are the same price and one is offering 1080i and the other 780p i was just wondering which one is better for the money.

More lines of resolution always wins.

Now.

Every TV displays SD differently. Honestly, you'll need to view them and make your own decision. For me, and I used to sell them all, I bought the Sony 55" SXRD rear projections. All other TVs be they flat panel or RP, had trouble displaying SD programming (because SD is 480 and the TVs upconvert a little differently). They all had artifacts like mosquito noise and the screen door effect. Very pronounced on some of them. My Sony has none of that. None, period. And HD looks like film. And these are the facts and they are undisputed. My TV cost more. And I got more.

It sounds like there might be some confusion between 1080i and 1080p. First off, the "p" behind the number means progressive and the "i" means interlace. For 720p, the TV displays 720 horizonal lines all at once, whereas a 1080i TV displays only half of it's 1080 horizontal lines, so for every frame of video, 1080i must display 540 lines twice. The number of 1080i is a bit misleading. I think it should technically be called 540i. They both look stunning on slow moving HD content. When some fast moving action is displayed, you may see some edges or softer images on 1080i because the image is moving faster than the TV can display both passes of 540 lines cleanly. The 720p won't show as much aliasing around diagonal edges when fast action happens. Most sports fans I've spoken to prefer 720p.
Now, part 2 of the lesson: 1080p is like 720p whereas the entire 1080 lines of resolution are displayed at once. In theory, this will give the best image. Problem is, no broadcast station can send 1080p because of the HUGE bandwidth it would require to get the signal over the air. The 1080p TVs would make sense if you hook up a device capable of real 1080p display, like the Sony PS3 or a new BlueRay DVD player.
Lesson 3: How a TV looks when it displays SD material isn't so much a matter of 720p vs 1080i, it's dependent on the video scaler that the TV maker puts into the set.
Lesson 4: HDTVs generally look crummy when displaying SD materail. SD material may have 240 horizontallines of resolution. When you have a TV that has a native resolution of 720p or 1080i (actually 540), how do you think the TV fills in the extra 400 lines of resolution? The TV's scaler re-scales the signal up to it's native resolution. Again, the quality of this process depends a lot on the quality of the scaler the company puts into the TV. I can guarantee you that the Kodak LCD TV won't have the same quality video scaler as the Sony XBR.
Lesson 5: It doesn't matter if you have a TV that is 720p, 1080i or 1080p, it will take whatever signal you give it and rescale it to it's native resolution. Again, the quality of this process depends on the quality of the video scaler the company puts in the TV.

That was really well put. That is a fact that is lost on most people. I have seen some plasma TVs that just look horrible in SD although they look great in HD. It is the scaler, not the screen. I am very happy with the job my Panasonic plasma does scaling an SD source. While SD does not come near HD quality on this set, some programs do approach DVD quality. I use Dishnetwork and some of the signals are very clear and display very well on the set. Of course, a bad source will give you a lousy picture no matter how good the scaler.

Dan's explaination is the very reason that you need to get out and look at the sets you want to buy and look at them with SD sources as well as HD. Remember, we will still be looking at a lot of SD programming for a while.

Now for 720p vs 1080i. If you were looking at s static or very slow moving picture, 1080i would look sharper because you are displaying 1080 lines of resolution quickly enough that it appears to be displayed all at once. Once you begin to put motion into the picture, the 720P will look sharper because it is displaying all 720 lines at once instead of every other line. You will not get the blur with 720p that you will with 1080i. That said, see lession #5.

When displaying an interlaced picture, the TV scans the odd lines; 1, 3, 5, 7, and so on in 1/60th of a second. Then the even lines; 2, 4, 6, 8, etc. in 1/60th of a second. This gives a full picture in 1/30th of a second. Progressive scan scans all the lines in 1/60th of a second.

In essence, interlaced displays the picture in two passes, progressive scan in one pass.

One correction, please. Progressive frame rate is 24 or 30 fps (controlled by the content provider). The interlaced "field rate" is 60 fields per second -- a "field" being a full set of odd or a full set even numbered lines in a frame.

The 24 fps frame rate is for correct emulation of film images without requiring the 2:3 frame conversion to 30 fps that TV normally requires. (Sound film is 24fps while video _frame_ rate has always been 30fps.)

All of you saved me a lot of typing!! Thanks!!!
As for the quality of SD scalers in HDTV there is no listing for the good ones! Sadly it's hit or miss. The best thing to do is insist that you view SD on any HDTV before you take it home.
When watching SD on any HDTV keep in mind this.
The Cool Aid effect!
One pack of Cool Aid, two quarts of water, two cups of sugar, mix and drink. Now add two more quarts of water, it will still have some color and some taste, but won't be that same. This is kinda what happens when you watch SD on HDTVs. John

See my friend had an hd tv and i was just wondering why there is so much of the blur, so i decided to look into my own tvs and found that his was 1080i and the one i wanted is 780p. So i might as well get 780p sicne i play games and whatch sports. Now for the tv i think that i am going to get the http://reviews.cnet.com/Samsung_LN_S3251D/4505-6482_7-31787622.html?tag=pdtl-list (do any of you have opinions on it?). thanks for all of the recomemdations, i think that you have all guided me well on my choice. But i have one last question, how much HD can i get over an antenna? Is it 780p or 1080i or what?

Each station decides its own content. Some broadcast in 1080, some in 720.

How many stations you get depends on where you live. This site should answer all your ATA questions.

http://www.antennaweb.org/aw/welcome.aspx

Who makes the best scaler technology? Is there a site that has reviews of the scalers?

After all the reading and now with changes in the market, it appears that a 42"(or so) 1080p will be the way to go. But being under the thumb of Comcast, I'll need to be able to depend on getting good quality from 720p and from some SD for few years yet.

Where can I find usuable reviews of the scalers used in different sets.

Trying to "see" them at a store is almost useless. (almost.) Some stores have no SD hookup or they won't show it to you. Some stores have no HD ( ! ) and that's a clue that they don't know what they're doing anyway so you don't know if you're getting the best possible setup in content delivery and set setup/tuning for the signal. (You scratch your head at a room full of TV's and wonder what the manufacturers where thinking to put these sets on the market -- even though you realize you couldn't be seeing the best image quality.)

So anyway; is there some place where somebody has reviewed the scaler technology in a useful way?